1. Field of the Invention
This invention relates to the field of protein kinases and inhibitors thereof. In particular, the invention relates to inhibitors of mammalian target of rapamycin (mTOR) signaling pathways, and methods of their use.
2. Background of the Invention
Phosphatidylinositol 3-kinase (PI3Kα), a dual specificity protein kinase, is composed of an 85 kDa regulatory subunit and a 110 kDa catalytic subunit. The protein encoded by this gene represents the catalytic subunit, which uses ATP to phosphorylate PtdIns, PtdIns4P and PtdIns(4,5)P2. PTEN, a tumor suppressor which inhibits cell growth through multiple mechanisms, can dephosphorylate PIP3, the major product of PIK3CA. PIP3, in turn, is required for translocation of protein kinase B (AKT1, PKB) to the cell membrane, where it is phosphorylated and activated by upstream kinases. The effect of PTEN on cell death is mediated through the PIK3CA/AKT1 pathway.
PI3Kα has been implicated in the control of cytoskeletal reorganization, apoptosis, vesicular trafficking, proliferation and differentiation processes. Increased copy number and expression of PIK3CA is associated with a number of malignancies such as ovarian cancer (Campbell et al., Cancer Res 2004, 64, 7678-7681; Levine et al., Clin Cancer Res 2005, 11, 2875-2878; Wang et al., Hum Mutat 2005, 25, 322; Lee et al., Gynecol Oncol 2005, 97, 26-34), cervical cancer, breast cancer (Bachman, et al. Cancer Biol Ther 2004, 3, 772-775; Levine, et al., supra; Li et al., Breast Cancer Res Treat 2006, 96, 91-95; Saal et al., Cancer Res 2005, 65, 2554-2559; Samuels and Velculescu, Cell Cycle 2004, 3, 1221-1224), colorectal cancer (Samuels, et al. Science 2004, 304, 554; Velho et al. Eur J Cancer 2005, 41, 1649-1654), endometrial cancer (Oda et al. Cancer Res. 2005, 65, 10669-10673), gastric carcinomas (Byun et al., Int J Cancer 2003, 104, 318-327; Li et al., supra; Velho et al., supra; Lee et al., Oncogene 2005, 24, 1477-1480), hepatocellular carcinoma (Lee et al., id.), small and non-small cell lung cancer (Tang et al., Lung Cancer 2006, 51, 181-191; Massion et al., Am J Respir Crit. Care Med 2004, 170, 1088-1094), thyroid carcinoma (Wu et al., J Clin Endocrinol Metab 2005, 90, 4688-4693), acute myelogenous leukemia (AML) (Sujobert et al., Blood 1997, 106, 1063-1066), chronic myelogenous leukemia (CML) (Hickey and Cotter J Biol Chem 2006, 281, 2441-2450), and glioblastomas (Hartmann et al. Acta Neuropathol (Berl) 2005, 109, 639-642; Samuels et al., supra).
The mammalian target, mTOR, is a protein kinase that integrates both extracellular and intracellular signals of cellular growth, proliferation, and survival. Extracellular mitogenic growth factor signaling from cell surface receptors and intracellular pathways that convey hypoxic stress, energy and nutrient status all converge at mTOR. mTOR exists in two distinct complexes: mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2). mTORC1 is a key mediator of transcription and cell growth (via its substrates p70S6 kinase and 4E-BP1) and promotes cell survival via the serum and glucocorticoid-activated kinase SGK, whereas mTORC2 promotes activation of the pro-survival kinase AKT. Given its central role in cellular growth, proliferation and survival, it is perhaps not surprising that mTOR signaling is frequently dysregulated in cancer and other diseases (Bjornsti and Houghton Rev Cancer 2004, 4(5), 335-48; Houghton and Huang Microbiol Immunol 2004, 279, 339-59; Inoki, Corradetti et al. Nat Genet. 2005, 37(1), 19-24).
mTOR is a member of the PIKK (PI3K-related Kinase) family of atypical kinases which includes ATM, ATR, and DNAPK, and its catalytic domain is homologous to that of PI3K. Dyregulation of PI3K signaling is a common function of tumor cells. In general, mTOR inhibition may be considered as a strategy in many of the tumor types in which PI3K signaling is implicated such as those discussed below.
Inhibitors of mTOR may be useful in treating a number of cancers, including the following: breast cancer (Nagata, Lan et al., Cancer Cell 2004, 6(2), 117-27; Pandolfi N Engl J Med 2004, 351(22), 2337-8; Nahta, Yu et al. Nat Clin Pract Oncol 2006, 3(5), 269-280); antle cell lymphoma (MCL) (Dal Col, Zancai et al. Blood 2008, 111(10), 5142-51); renal cell carcinoma (Thomas, Tran et al. Nat Med 2006, 12(1), 122-7; Atkins, Hidalgo et al. J Clin Oncol 2004, 22(5), 909-18; Motzer, Hudes et al. J Clin Oncol 2007, 25(25), 3958-64); acute myelogenous leukemia (AML) (Sujobert, Bardet et al. Blood 2005, 106(3), 1063-6; Billottet, Grandage et al. Oncogene 2006, 25(50), 6648-6659; Tamburini, Elie et al. Blood 2007, 110(3), 1025-8); chronic myelogenous leukemia (CML) (Skorski, Bellacosa et al. Embo J 1997, 16(20), 6151-61; Bai, Ouyang et al. Blood 2000, 96(13), 4319-27; Hickey and Cotter Biol Chem 2006, 281(5), 2441-50); diffuse large B cell lymphoma (DLBCL) (Uddin, Hussain et al. Blood 2006, 108(13), 4178-86); several subtypes of sarcoma (Hernando, Charytonowicz et al. Nat Med 2007, 13(6), 748-53; Wan and Helman Oncologist 2007, 12(8), 1007-18); rhabdomyosarcoma (Cao, Yu et al. Cancer Res 2008, 68(19), 8039-8048; Wan, Shen et al. Neoplasia 2006, 8(5), 394-401); ovarian cancer (Shayesteh, Lu et al. Nat Genet, 1999, 21(1), 99-102; (Lee, Choi et al. Gynecol Oncol 2005, 97(1) 26-34); endometrial tumors (Obata, Morland et al. Cancer Res 1998, 58(10), 2095-7; Lu, Wu et al. Clin Cancer Res 2008, 14(9), 2543-50); non small cell lung carcinoma (NSCLC) (Tang, He et al. Lung Cancer 2006, 51(2), 181-91; Marsit, Zheng et al. Hum Pathol 2005, 36(7), 768-76); small cell, squamous, large cell and adenocarcinoma (Massion, Taflan et al. Am J Respir Crit. Care Med 2004, 170(10), 1088-94); lung tumors in general (Kokubo, Gemma et al. Br J Cancer 2005, 92(9), 1711-9; Pao, Wang et al. Pub Library of Science Med 2005, 2(1), e17); colorectal tumors (Velho, Oliveira et al. Eur J Cancer 2005, 41(11), 1649-54; Foukas, Claret et al. Nature, 2006, 441(7091), 366-370), particularly those that display microsatellite instability (Goel, Arnold et al. Cancer Res 2004, 64(9), 3014-21; Nassif, Lobo et al. Oncogene 2004, 23(2), 617-28), KRAS-mutated colorectal tumors (Bos Cancer Res 1989. 49(17), 4682-9; Fearon Ann N Y Acad Sci 1995, 768, 101-10); gastric carcinomas (Byun, Cho et al. Int J Cancer 2003, 104(3), 318-27); hepatocellular tumors (Lee, Soung et al. Oncogene 2005, 24(8), 1477-80); liver tumors (Hu, Huang et al. Cancer 2003, 97(8), 1929-40; Wan, Jiang et al. Cancer Res Clin Oncol 2003, 129(2), 100-6); primary melanomas and associated increased tumor thickness (Guldberg, thor Staten et al. Cancer Res 1997, 57(17), 3660-3; Tsao, Zhang et al. Cancer Res 2000, 60(7), 1800-4; Whiteman, Zhou et al. Int J Cancer 2002, 99(1), 63-7; Goel, Lazar et al. J Invest Dermatol 126(1), 2006, 154-60); pancreatic tumors (Asano, Yao et al. Oncogene 2004, 23(53), 8571-80); prostate carcinoma (Cairns, Okami et al. Cancer Res 1997, 57(22), 4997-5000; Gray, Stewart et al. Br J Cancer 1998, 78(10), 1296-300; Wang, Parsons et al. Clin Cancer Res 1998, 4(3), 811-5; Whang, Wu et al. Proc Natl Acad Sci USA 1998, 95(9), 5246-50; Majumder and Sellers Oncogene 2005, 24(50) 7465-74; Wang, Garcia et al. Proc Natl Acad Sci USA 2006, 103(5), 1480-5; (Lu, Ren et al. Int J Oncol 2006, 28(1), 245-51; Mulholland, Dedhar et al. Oncogene 25(3), 2006, 329-37; Xin, Teitell et al. Proc Natl Acad Sci USA 12006, 03(20), 7789-94; Mikhailova, Wang et al. Adv Exp Med Biol 2008, 617, 397-405; Wang, Mikhailova et al. Oncogene 2008, 27(56), 7106-7117); thyroid carcinoma, particularly in the anaplastic subtype (Garcia-Rostan, Costa et al. Cancer Res 2005, 65(22), 10199-207); follicular thyroid carcinoma (Wu, Mambo et al. J Clin Endocrinol Metab 2005, 90(8), 4688-93); anaplastic large cell lymphoma (ALCL); hamaratomas, angiomyelolipomas, TSC-associated and sporadic lymphangioleiomyomatosis: Cowden's disease (multiple hamaratoma syndrome) (Bissler, McCormack et al. N Engl J Med 2008, 358(2), 140-151); sclerosing hemangioma (Randa M. S. Amin Pathology International 2008, 58(1), 38-44); Peutz-Jeghers syndrome (PJS); head and neck cancer (Gupta, McKenna et al. Clin Cancer Res 2002, 8(3), 885-892); neurofibromatosis (Ferner Eur J Hum Genet. 2006, 15(2), 131-138; Sabatini Nat Rev Cancer 2006, 6(9), 729-734; Johannessen, Johnson et al. Current Biology 2008, 18(1), 56-62); macular degeneration; macular edema; myeloid leukemia; systemic lupus; and autoimmune lymphoproliferative syndrome (ALPS).